java 如何为文件及文件夹添加权限

• • 2.acl文件权限
  • 3.posix文件权限

java 为文件及文件夹添加权限

/**
 * 增加权限，使路径可上传文件
 */
public static void addchmod777(string filepath) throws ioexception {
	if (!system.getproperty("os.name").startswith("win")) {
		string cmdgrant = "chmod 777 " + filepath;
		baselogmethod.loginfo(tag, "file augmentation after moving:" + cmdgrant);
		runtime.getruntime().exec(cmdgrant);
	}
}
/**
 * 增加权限，使路径及子路径都有权限
 */
public static void addrchmod777(string filepath) throws ioexception {
	if (!system.getproperty("os.name").startswith("win")) {
		string cmdgrant = "chmod -r 777 " + filepath;
		baselogmethod.loginfo(tag, ".addrchmod777: file augmentation after moving:" + cmdgrant);
		runtime.getruntime().exec(cmdgrant);
	}
}

java 修改文件所有者及其权限

1.设置所有者

管理文件所有者

files.getowner()和files.setowner()方法

要使用userprincipal来管理文件的所有者

（1）更改文件的所有者

import java.io.ioexception;
import java.nio.file.*;
import java.nio.file.attribute.fileownerattributeview;
import java.nio.file.attribute.userprincipal;
import java.nio.file.attribute.userprincipallookupservice;
public class main {
    public static void main(string[] args) {
        path path = paths.get("/www/test1.txt");
        fileownerattributeview foav = files.getfileattributeview(path,
                fileownerattributeview.class);
        try {
            userprincipal owner = foav.getowner();
            system.out.format("original owner  of  %s  is %s%n", path,
                    owner.getname());
            filesystem fs = filesystems.getdefault();
            userprincipallookupservice upls = fs.getuserprincipallookupservice();
            userprincipal newowner = upls.lookupprincipalbyname("abc");
            foav.setowner(newowner);
            userprincipal changedowner = foav.getowner();
            system.out.format("new owner  of  %s  is %s%n", path,
                    changedowner.getname());
        }catch (ioexception e){
            e.printstacktrace();
        }
    }
}

输出

查看文件详细信息

2.acl文件权限

windows上支持acl类型文件属性

使用aclfileattributeview的

• getacl()方法获取文件的aclentry列表
• setacl()方法设置文件的aclentry列表

（1）读取文件e:/test1.txt的acl条目

import java.io.ioexception;
import java.nio.file.files;
import java.nio.file.path;
import java.nio.file.paths;
import java.nio.file.attribute.aclentry;
import java.nio.file.attribute.aclentrypermission;
import java.nio.file.attribute.aclfileattributeview;
import java.util.list;
import java.util.set;
public class main {
    public static void main(string[] args) {       
        path path = paths.get("e:/test1.txt");
        aclfileattributeview aclview = files.getfileattributeview(path,
                aclfileattributeview.class);
        if (aclview == null) {
            system.out.format("acl view  is not  supported.%n");
            return;
        }
        try {
            list<aclentry> aclentries = aclview.getacl();
            for (aclentry entry : aclentries) {
                system.out.format("principal: %s%n", entry.principal());
                system.out.format("type: %s%n", entry.type());
                system.out.format("permissions are:%n");
                set<aclentrypermission> permissions = entry.permissions();
                for (aclentrypermission p : permissions) {
                    system.out.format("%s %n", p);
                }
            }
        } catch (ioexception e) {
            e.printstacktrace();
        }
    }
}

输出结果为

principal: builtin\administrators (alias)
type: allow
permissions are:
write_data
write_owner
append_data
synchronize
write_attributes
execute
read_data
delete_child
read_attributes
write_named_attrs
write_acl
delete
read_acl
read_named_attrs
principal: nt authority\system (well-known group)
type: allow
permissions are:
write_data
write_owner
append_data
synchronize
write_attributes
execute
read_data
delete_child
read_attributes
write_named_attrs
write_acl
delete
read_acl
read_named_attrs
principal: nt authority\authenticated users (well-known group)
type: allow
permissions are:
write_data
read_attributes
append_data
write_named_attrs
synchronize
write_attributes
execute
delete
read_data
read_acl
read_named_attrs
principal: builtin\users (alias)
type: allow
permissions are:
read_attributes
synchronize
execute
read_data
read_acl
read_named_attrs

（2）为指定用户添加新的acl条目

e:/test1.txt为用户abc添加data_read和data_ write权限

import java.io.ioexception;
import java.nio.file.filesystems;
import java.nio.file.files;
import java.nio.file.path;
import java.nio.file.paths;
import java.nio.file.attribute.*;
import java.util.enumset;
import java.util.list;
import java.util.set;
import static java.nio.file.attribute.aclentrypermission.read_data;
import static java.nio.file.attribute.aclentrypermission.write_data;
public class main {
    public static void main(string[] args) {
        
        path path = paths.get("e:/test1.txt");
        aclfileattributeview aclview = files.getfileattributeview(path,
                aclfileattributeview.class);
        if (aclview == null) {
            system.out.format("acl view  is not  supported.%n");
            return;
        }
        try {
            userprincipal briceuser = filesystems.getdefault()
                    .getuserprincipallookupservice().lookupprincipalbyname("abc");
            set<aclentrypermission> permissions = enumset.of(read_data, write_data);
            aclentry.builder builder = aclentry.newbuilder();
            builder.setprincipal(briceuser);
            builder.settype(aclentrytype.allow);
            builder.setpermissions(permissions);
            aclentry newentry = builder.build();
            list<aclentry> aclentries = aclview.getacl();
            aclentries.add(newentry);
            aclview.setacl(aclentries);
        }catch (ioexception e){
            e.printstacktrace();
        }
    }
}

输出结果比刚才多了

principal: hkgi-pc\abc (user)
type: allow
permissions are:
write_data
read_data

3.posix文件权限

unix支持posix标准文件属性

posixfilepermission枚举类型定义九个常量，每个权限组件一个。

九个常数命名为x_y，其中x是owner，group和others，y是read，write和execute。

• posixfilepermissions的tostring()方法将一组posixfilepermission枚举常量转换为rwxrwxrwx形式的字符串
• posixfileattributeview的setpermissions()方法用来设置权限

（1）输出/www/test1.txt的权限

import java.io.ioexception;
import java.nio.file.files;
import java.nio.file.path;
import java.nio.file.paths;
import java.nio.file.attribute.*;
import java.util.set;
public class main {
    public static void main(string[] args) {
        path path = paths.get("/www/test1.txt");
        posixfileattributeview posixview = files.getfileattributeview(path,
                posixfileattributeview.class);
        try{
            posixfileattributes attribs = posixview.readattributes();
            set<posixfilepermission> permissions = attribs.permissions();
            // convert the file permissions into the rwxrwxrwx string form
            string rwxformpermissions = posixfilepermissions.tostring(permissions);
            // print the permissions
            system.out.println(rwxformpermissions);
        }catch (ioexception e){
            e.printstacktrace();
        }
    }
}

输出结果

rw-r--r--

（2）读取和更新名为test的文件权限

import java.io.ioexception;
import java.nio.file.files;
import java.nio.file.path;
import java.nio.file.paths;
import java.nio.file.attribute.*;
import java.util.enumset;
import java.util.set;
import static java.nio.file.attribute.posixfilepermission.*;
public class main {
    public static void main(string[] args) {
        path path = paths.get("/www/test1.txt");
        posixfileattributeview posixview = files.getfileattributeview(path,
                posixfileattributeview.class);
        if (posixview == null) {
            system.out.format("posix attribute view  is not  supported%n.");
            return;
        }
        system.out.println("old:");
        readpermissions(posixview);
        updatepermissions(posixview);
        system.out.println("new:");
        readpermissions(posixview);
    }
    public static void readpermissions(posixfileattributeview posixview) {
        try{
            posixfileattributes attribs;
            attribs = posixview.readattributes();
            set<posixfilepermission> permissions = attribs.permissions();
            // convert the set of posix file permissions into rwxrwxrwx form
            string rwxformpermissions = posixfilepermissions.tostring(permissions);
            system.out.println(rwxformpermissions);
        }catch (ioexception e){
            e.printstacktrace();
        }
    }
    public static void updatepermissions(posixfileattributeview posixview) {
        try {
            set<posixfilepermission> permissions = enumset.of(owner_read, owner_write,owner_execute,
                    group_read,group_write);
            posixview.setpermissions(permissions);
            system.out.println("permissions set successfully.");
        }catch (ioexception e){
            e.printstacktrace();
        }
    }
}

输出结果

old:
rw-r-----
permissions set successfully.
new:
rwxrw----

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。